吉林地区一次雷暴云个例电和云微物理特征的模拟分析   总被引：2，自引：1，他引：1       下载免费PDF全文

王芳  肖稳安  雷恒池  侯团结 《高原气象》2009,28(2):385-394

利用三维强风暴动力一电藕合数值模式, 结合闪电定位仪资料、雷达回波资料及降水资料,分析了吉林地区一次雷暴云个例在发生第一次闪电前云内电场的发展情况及微物理变化过程,并与青藏高原一次典型雷暴过程进行了对比.结果表明:云发展成熟时,云中呈现上正下负及云下部次正的三极性分布,主负电荷区稳定在-10℃层附近,次正电荷区浓度较大;上升气流穿过-15℃层之上开始强起电;云中最大电场出现在上升速度达到最大值后回落的阶段;闪电频数与云发展的高度及回波强度有关,回波强度＞45 dBz时,云发展越高,闪电频数越大,云顶高度＜6 km时,闪电发生较少;青藏高原雷暴具有与我国北方雷暴明显不同的特征.  相似文献   

Public-space planning in four Nordic cities: Symbolic values in tension     

Merle Jacob  Tomas Hellström 《Geoforum》2010,41(4):657-665

This article takes its point of departure in the assumption that values shape planning practices and that alternatively one can reconstruct such values from the way planning interventions are argued and evaluated. We contend that planners’ discourses involve implicit value commitments that are observable in their representations of public space and implicated in the results of public-space planning. The paper builds an empirical case from representations of public space elaborated in planning documents developed by planners in four medium-sized Nordic cities. We show how these planning representations form four thematic value clusters concerning urban public space, namely leisure-play, identity-unity, power-organization and unruliness-change. Together these clusters constitute a value framework which reveals a number of central tensions relating to the way that planners seek to balance order and spontaneity in public space. The paper concludes by outlining and discussing these values and the tensions they represent.  相似文献   

国外规划实施评价理论与方法及其在国内应用的研究进展     

平宗莉  闫整 《山东地质》2010,(2):33-36

在我国,修编土地利用总体规划、城市总体规划之前,开展对现行规划实施情况的评价,已经纳入规范的工作程序,与之相应,规划实施评价研究逐渐成为关注的焦点。该文首先对国外规划实施评价理论与方法进行简要的介绍,再对国内开展的实证研究进行归纳分类,并做出简要评述,以期为今后的规划实施评价研究提供一些新的视角和参考。  相似文献   

莱芜市钢城区畜禽养殖用地管理的现状及建议     

王胜军  鹿庆龙 《山东地质》2010,(5):41-42

随着我国畜牧业的发展,饲养方式和结构发生了很大的变化,对规模化养殖提出了新的要求,该文结合莱芜市钢城区实际,对畜牧养殖用地方面当前存在问题进行了系统的分析,对今后的用地管理提出了切实可行的建议。  相似文献   

平度市国土资源局全面推进“双保”行动的探索     

王强先 《山东地质》2010,(5):55-56,59

为应对国际金融危机,平度市国土资源局积极响应国土资源部在全国范围内部署开展的＂保增长、保红线＂双保行动,立足部门职能,扎实工作,加强和改善土地宏观调控新机制,有效保障扩大内需,保障重点项目用地,促进经济平稳较快发展。  相似文献   

一次人工触发闪电事件的定位误差分析   总被引：3，自引：1，他引：2  

陈绿文  黄智慧  禹继  李斌  黄国开 《广东气象》2010,32(1):15-17,21

利用一次包含8次回击过程的人工触发闪电事件的近距离光电观测数据,分析了广东省气象闪电定位系统对其回击过程的定位结果。结果表明,回击过程探测效率约为75%(6/8),回击平均定位误差约为3768m。为了分析定位误差来源,通过对比分析的方法,逐次引入各探测子站原始记录重新进行定位计算,发现剔除误差较大的探测子站后,平均定位误差为2192m,比原来降低42%。  相似文献   

贵州普定后寨河流域土壤侵蚀模型与应用研究   总被引：11，自引：0，他引：11  

汪文富 《贵州地质》2001,18(2):99-106

在典型岩溶区，由于喀斯特的强烈发育，自然条件差，加上人为因素的不良影响（毁林开荒、乱砍滥伐等），水土流失问题十分严重。随着遥感（Remote Sensing)技术的飞跃发展，计算机技术有普遍应用，特别是近年来地理信息系统（GIS）研究的迅速发展与应用，使土壤侵蚀研究从土壤侵蚀类型、分类、侵蚀地貌、侵蚀模数等定性、定量研究深入到潜在危害的研究阶段。本文是前人研究工作的基础上，以普定后寨河岩溶流域（普定岩溶野外试验场）为研究区，利用遥感（RS）和地理信息系统（GIS）技术建立起适合于岩溶流域使用的土壤侵蚀定量模型，并在PAMAP GIS的支持下，探讨了利用遥感信息、GIS自动提取土壤侵蚀因子，最后得到流域实际的土壤侵蚀图、潜在的土壤侵蚀图等一系列图件，为岩溶流域的综合治理提供有效的理论研究依据。  相似文献   

GIS-based geo-environmental evaluation for urban land-use planning: a case study   总被引：34，自引：0，他引：34  

F. C. Dai  C. F. Lee  X. H. Zhang 《Engineering Geology》2001,61(4):257-271

A geo-environmental evaluation for urban land-use planning often requires a large amount of spatial information. Geographic information systems (GIS) are capable of managing large amounts of spatially related information, providing the ability to integrate multiple layers of information and to derive additional information. A GIS-aid to the geo-environmental evaluation for urban land-use planning is illustrated for the urban area of Lanzhou City and its vicinity in Northwest China. This evaluation incorporates topography, surficial and bedrock geology, groundwater conditions, and historic geologic hazards. Urban land-use is categorized according to the types of land-use and projects planned, such as high-rise building, multi-storey building, low-rise building, waste disposal, and natural conservation. Multi-criteria analysis is performed to evaluate development suitability of the geo-environment for each category, according to appropriately measured and weighted factors. A suitability map for each category is developed using an algorithm that combines factors in weighted linear combinations. It is demonstrated that the GIS methodology has high functionality for geo-environmental assessment.  相似文献   

成都数字遥测地震台网地震速报几个定位软件的比较与讨论   总被引：3，自引：1，他引：3  

汪碧澜  苏国君 《四川地震》2001,(2):29-34

应用成都数字遥测地震台网数据,通过对震中距大于300千米的55次地震重新定位,对比研究成都数字遥测地震台网数据处理软件提供的几种地震定位程序以及原模拟台网使用的地震定位程序,初步认为震中距在300千米<Δ≤10°时,Genetic、Gerlor-P、Gelor-I程序优于Front和loc212程序,而Telloc、loc312程序基本不能用;震中距在10°<Δ≤20°和20°<Δ≤50°时的地震定位,Front优于loc212程序,而Telloc程序不能用.  相似文献   

Remote sensing and GIS-based regional geomorphological mapping—a tool for land use planning in developing countries     

G. Bocco  M. Mendoza  A. Velzquez 《Geomorphology》2001,39(3-4)

Land use planning and necessary supporting data are crucial to developing countries that are usually under severe environmental and demographic strains. Approaches and methods to map the variability of natural resources are important tools to properly guide spatial planning. In this paper, we describe a method to quickly map terrain at reconnaissance (1:250,000) and semi-detailed (1:50,000) levels. This method can be utilized as a basis for further land evaluation and land use planning in large territories. The approach was tested in the state of Michoacan, central-western Mexico, currently undergoing rapid deforestation and subsequent land degradation.Results at the reconnaissance level describe the geographic distribution of major landforms and dominant land cover, and provide a synoptic inventory of natural resources. Results at the semi-detailed level indicate how to nest individual landforms to major units and how they can be used to run procedures for land evaluation. If combined with appropriate socioeconomic data, governmental guidelines for land use planning can be formulated on the basis of reconnaissance and semi-detailed terrain analysis.  相似文献